Mirror with image display function

ABSTRACT

According to the invention, there is provided a mirror with an image display function including, in this order: an image display device; a circular polarization reflection layer; and a front surface plate made of glass or plastic, in which the circular polarization reflection layer includes a cholesteric liquid crystal layer, the cholesteric liquid crystal layer has a central wavelength of selective reflection in a visible light region, and the central wavelength is different from an emission peak wavelength of the image display device by 5 nm or greater. The mirror with an image display function of the invention is capable of displaying a bright image.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT International Application No.PCT/JP2015/083564 filed on Nov. 30, 2015, which claims priority under 35U.S.C § 119(a) to Japanese Patent Application No. 2014-243443 filed onDec. 1, 2014, the entire content of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mirror with an image displayfunction.

2. Description of the Related Art

For example, image display devices with a mirror function, in which ahalf mirror is provided on a surface of an image display portion of theimage display device to allow the mirror to display an image in adisplay mode and to allow the minor to function as a mirror in anon-display mode such as a power-off mode of the image display device,are described in JP2002-229494A, JP2011-45427A, and JP2014-201146A.

SUMMARY OF THE INVENTION

In general, the visible light transmittance of a half mirror isapproximately 30% to 70%, and a configuration in which a half mirror isprovided on a surface of an image display portion has a potentialproblem in that an image appears darker than that in a configurationwith no half mirror. An object of the invention is to solve the problem.That is, an abject of the invention is to provide a minor with an imagedisplay function capable of displaying a brighter image.

The inventors have conducted intensive studies to achieve the object,and thought of an optical design of a half minor in consideration ofcharacteristics of light for image display. Based on this thought, theinventors have performed optical design and produced a half mirror usinga material suitable for the optical design, and thus completed theinvention.

That is, the invention provides the following [1]to [9].

[1] A mirror with an image display function comprising, in this order:an image display device; a circular polarization reflection layer; and afront surface plate made of glass or plastic, in which the circularpolarization reflection layer includes a cholesteric liquid crystallayer, the cholesteric liquid crystal layer has a central wavelength ofselective reflection in a visible light region, and the centralwavelength is different from an emission peak wavelength of the imagedisplay device by 5 nm or greater.

[2] The mirror with an image display function according to [1], in whichthe circular polarization reflection layer includes two or morecholesteric liquid crystal layers, and the two or more cholestericliquid crystal layers have different central wavelengths of selectivereflection.

[3] The mirror with an image display function according to [2], in whichthe two or more cholesteric liquid crystal layers are in direct contactwith each other.

[4] The mirror with an image display function according to any one [1]to [3], in which the image display device shows an emission peakwavelength λR of red light, an emission peak wavelength λG of greenlight, and an emission peak wavelength λB of blue light in an emissionspectrum during white display, and any one of the central wavelengths ofselective reflection of the cholesteric liquid crystal layers isdifferent from any one of λR, λG, and λB by 5 nm or greater.

[5] The mirror with an image display function according to [4], in whichthe circular polarization reflection layer includes three or morecholesteric liquid crystal layers, and the three or more cholestericliquid crystal layers have different central wavelengths of selectivereflection.

[6] The mirror with an image display function according to [5], in whichthe circular polarization reflection layer includes layers in whichcholesteric liquid crystalline phases having λ1, λ2, and λ3respectively, are fixed as different central wavelengths of selectivereflection, and a relationship of λB<λ1<λG<λ2<λR<λ3 is satisfied.

[7] The mirror with an image display function according to [5] or [6] inwhich in the circular polarization reflection layer, a cholestericliquid crystal layer having a longer central wavelength of selectivereflection is disposed closer to the image display device.

[8] The mirror with an image display function according to any one of[1] to [7], in which the circular polarization reflection layer includesa cholesteric liquid crystal layer having a central wavelength ofselective reflection in an infrared light region.

[9] The mirror with an image display function according to any one of[1] to [8], in which the image display device and the circularpolarization reflection layer are directly adhered to each other throughan adhesive layer.

According to the invention, there is provided a novel mirror with animage display function. The mirror with an image display function of theinvention is capable of displaying a brighter image. In addition, themirror with an image display function of the invention is good in termsof the front tint even when being used as a mirror. In addition, theminor with an image display function of the invention has an advantagein that minor-reflected images can be observed even through polarizedsunglasses without direction dependency.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the invention will be described in detail.

In this specification, “to” is used to mean that numerical values beforeand after “to” are included as a lower limit value and an upper limitvalue.

In this specification, an angle such as “45°”, “parallel”, “vertical”,or “perpendicular” means that a difference from an exact angle is in arange less than 5 degrees unless otherwise stated. The difference froman exact angle is preferably less than 4 degrees, and more preferablyless than 3 degrees.

In this specification, “(meth)acrylate” is used to mean “one or both ofacrylate and methacrylate”.

In this specification, when “selectively” is used in regard tocircularly polarized light, it means that the light quantity of any oneof a right circular polarization component and a left circularpolarization component of emitted light is greater than that of theother circular polarization component. Specifically, when “selectively”is used, the circular polarization degree of light is preferably 0.3 orgreater, more preferably 0.6 or greater, and even more preferably 0.8 orgreater. Substantially, the circular polarization degree is yet evenmore preferably 1.0.

Here, the circular polarization degree is a value which is expressed by|I_(R)−I_(L)|/(I_(R)+I_(L)) where the intensity of a right circularpolarization component of light is represented by I_(R), and theintensity of a left circular polarization component is represented byI_(L).

In this specification, when “sense” is used in regard to circularlypolarized light, it means that the light is either right-circularlypolarized light or left-circularly polarized light. The sense ofcircularly polarized light is defined such that, in a case where lightis viewed as it proceeds toward an observer and in a case where the tipof an electric field vector rotates clockwise with the increase in time,the light is right-circularly polarized light, and in a case where itrotates counterclockwise, the light is left-circularly polarized light.

In this specification, the term “sense” may be used in regard to atwisted direction of the helix of cholesteric liquid crystal. Regardingselective reflection by cholesteric liquid crystal, in a case where atwisted direction (sense) of the helix of the cholesteric liquid crystalis right-handed, the right-circularly polarized light is reflected andthe left-circularly polarized light is transmitted. In a case where thesense is left-handed, the left-circularly polarized light is reflected,and the right-circularly polarized light is transmitted.

In electromagnetic rays, visible light rays are light rays in awavelength region human's eyes can see, and refer to light in awavelength region of 380 nm to 780 nm. Infrared rays (infrared light)are electromagnetic rays in a wavelength region which is longer thanvisible light rays and shorter than radio waves. In infrared rays,near-infrared light refers to electromagnetic rays in a wavelengthregion of 780 nm to 2500 nm.

In this specification, when “image” is used in regard to a mirror withan image display function, it means an image which can be observed byvisually recognizing a half mirror from a front surface plate side whenan image display portion of an image display device displays the image.In addition, in this specification, when “mirror-reflected image” isused in regard to the mirror with an image display function, it means animage which can be observed by being visually recognized from a frontsurface plate when the image display portion of the image display devicedisplays no image.

<Mirror with Image Display Function>

A mirror with an image display function of the invention includes animage display device, a circular polarization reflection layer, and afront surface plate in this order. Between the image display device andthe circular polarization reflection layer, or between the circularpolarization reflection layer and the front surface plate, other layerssuch as an adhesive layer may be included or not included. It ispreferable that the circular polarization reflection layer and the frontsurface plate are directly adhered to each other. That is, the imagedisplay device and the circular polarization reflection layer may be indirect contact with each other, an air layer may exist therebetween, orthe image display device and the circular polarization reflection layermay be directly adhered to each other through an adhesive layer.

In this specification, a surface on the front surface plate side of thecircular polarization reflection layer may be a front surface.

The image display device may be adhered to the circular polarizationreflection layer in at least a part of the image display portion. Thearea of the surface of the circular polarization reflection layer to beadhered may be smaller than, the same as, or larger than that of theimage display portion.

The front surface plate may be larger than, the same as, or smaller thanthe circular polarization reflection layer. The circular polarizationreflection layer may be adhered to a part of the front surface plate,and another type of reflection layer such as metal foil may be adheredto or formed on the other portion of the front surface plate. In thisconfiguration, it is possible to display an image on a part of themirror. The circular polarization reflection layer may be adhered to theentire surface of the front surface plate, and the image display devicehaving an image display portion with the same area as the circularpolarization reflection layer may be adhered to the circularpolarization reflection layer in the image display portion. In thisconfiguration, it is possible to display an image on the entire surfaceof the mirror.

[Image Display Device]

The image display device is not particularly limited, but is preferablya liquid crystal display device.

The liquid crystal display device may be a transmission type or areflection type, and is particularly preferably a transmission type. Theliquid crystal display device may be a liquid crystal display device ofany one of an in plane switching (IPS) mode, a fringe field switching(FFS) mode, a vertical alignment (VA) mode, an electrically controlledbirefringence (ECB) mode, a super twisted nematic (STN) mode, a twistednematic (TN) mode, an optically compensated bend (OCB) mode, and thelike. The image which is displayed on the image display portion of theimage display device may be a still image, a motion picture, or simpletexture information. The display may be monochrome display such as blackand white display, multi-color display, or full-color display. The imagedisplay device preferably shows an emission peak wavelength λR of redlight, an emission peak wavelength λG of green light, and an emissionpeak wavelength λB of blue light in an emission spectrum during whitedisplay. Since the image display device has such emission peakwavelengths, it can display a full-color image. λR may be 580 to 700 nm,and preferably 610 to 680 nm. λG may be 500 to 580 nm, and preferably510 to 550 nm. λB may be 400 to 500 nm, and preferably 440 to 480 nm.

[Circular Polarization Reflection Layer]

The circular polarization reflection layer functions as asemitransmissive-semireflective layer in the mirror with an imagedisplay function. That is, the circular polarization reflection layerfunctions to transmit the light emitted from the image display deviceduring the image display such that the image is displayed on the frontsurface of the mirror with an image display function. During thenon-image display, the circular polarization reflection layer functionsto reflect at least a part of light incident in a front surface platedirection such that the front surface of the mirror with an imagedisplay function serves as a mirror.

In the mirror with an image display function of the invention, since thecircular polarization reflection layer is used, incidence rays from thefront surface can be reflected as circularly polarized light.Accordingly, in the mirror with an image display function of theinvention, it is possible to observe mirror-reflected images eventhrough polarized sunglasses without depending on the relationshipbetween the transmission axis direction of the polarized sunglasses andthe horizontal direction of the mirror with an image display function.

The circular polarization reflection layer includes at least onecholesteric liquid crystal layer exhibiting selective reflection in avisible light region. The circular polarization reflection layer mayinclude two or more cholesteric liquid crystal layers, and may includeother layers such as an alignment layer. The circular polarizationreflection layer preferably consists only of a cholesteric liquidcrystal layer. When the circular polarization reflection layer includesa plurality of cholesteric liquid crystal layers, these are preferablyin direct contact with an adjacent cholesteric liquid crystal layer. Thecircular polarization reflection layer preferably includes three or morecholesteric liquid crystal layers.

The film thickness of the circular polarization reflection layer ispreferably in a range of 2.0 μm to 300 μm, and more preferably in arange of 8.0 μm to 200 μm.

(Cholesteric Liquid Crystal Layer)

In this specification, the cholesteric liquid crystal layer means alayer in which a cholesteric liquid crystalline phase is fixed. Thecholesteric liquid crystal layer may be simply referred to as a liquidcrystal layer.

The cholesteric liquid crystalline phase has been known to exhibitcircular polarization selective reflection in which circularly polarizedlight of any one sense of either right-circularly polarized light orleft-circularly polarized light is selectively reflected and circularlypolarized light of the other sense is transmitted in a specificwavelength region. In this specification, the circular polarizationselective reflection may be simply referred to as selective reflection.

As a film including a layer in which a cholesteric liquid crystallinephase exhibiting circular polarization selective reflectivity is fixed,many films formed from a composition containing a polymerizable liquidcrystal compound have been known, and regarding the cholesteric liquidcrystal layer, the related arts can be referred to.

The cholesteric liquid crystal layer may be a layer in which alignmentof a liquid crystal compound in a cholesteric liquid crystalline phaseis held. Typically, the cholesteric liquid crystal layer may be a layerobtained in such a manner that a polymerizable liquid crystal compoundis allowed to be in an alignment state of a cholesteric liquidcrystalline phase, and polymerized and cured by ultraviolet irradiation,heating, or the like to form a layer having no fluidity, and at the sametime, the layer is changed such that the form of alignment is notchanged by an external field or an external force. In the cholestericliquid crystal layer, the optical properties of the cholesteric liquidcrystalline phase just need to be held in the layer, and the liquidcrystal compound in the layer may not exhibit liquid crystallinity. Forexample, the molecular weight of the polymerizable liquid crystalcompound may be increased by a curing reaction, and the liquidcrystallinity may be lost.

A central wavelength λ of selective reflection of the cholesteric liquidcrystal layer depends on a pitch P (periodicity of helix) of a helicalstructure in a cholesteric phase, and has a relationship of λ=n×P withan average refractive index n of the cholesteric liquid crystal layer.In this specification, the central wavelength λ of selective reflectionof the cholesteric liquid crystal layer means a wavelength at a centroidposition of a reflection peak of a circular polarization reflectionspectrum measured in a normal direction of the cholesteric liquidcrystal layer. In this specification, the central wavelength ofselective reflection means a central wavelength when measured in thenormal direction of the cholesteric liquid crystal layer.

As is obvious from the above formula, the central wavelength ofselective reflection can be adjusted by adjusting the pitch of thehelical structure. By adjusting the n value and the P value, any one ofright-circularly polarized light and left-circularly polarized light isselectively reflected with respect to light with a desired wavelength,and thus the central wavelength λ can be adjusted.

In a case where light is obliquely incident on the cholesteric liquidcrystal layer, the central wavelength of selective reflection shifts tothe short wavelength side. Therefore, with respect to the wavelength ofselective reflection necessary for image display, n×P is preferablyadjusted such that λ calculated in accordance with the above formulaλ=n×P becomes a long wavelength. When the central wavelength ofselective reflection when light rays pass through a cholesteric liquidcrystal layer with a refractive index n₂ in a normal direction of thecholesteric liquid crystal layer (a helical axis direction of thecholesteric liquid crystal layer) at an angle of θ₂ is represented byλ_(d), λ_(d) is expressed by the following formula.λ_(d) =n ₂ ×P×cos θ₂

By designing the central wavelength of selective reflection of thecholesteric liquid crystal layer included in the circular polarizationreflection layer in consideration of the above description, it ispossible to prevent oblique visibility of an image from being lowered.In addition, the oblique visibility of an image can be lowered. This isuseful since it is possible to prevent a peep in a case of, for example,a smartphone or a personal computer. In addition, in the mirror with animage display function of the invention, resulting from theabove-described selective reflection property, tint change may occur inimages and mirror-reflected images viewed in an oblique direction. Thetint change in a mirror-reflected image can be prevented in a case wherethe circular polarization reflection layer includes a cholesteric liquidcrystal layer having a central wavelength of selective reflection in aninfrared light region. In this case, the central wavelength of selectivereflection of the infrared light region may be specifically 780 to 900nm, and preferably 780 to 850 nm.

Since the pitch of the cholesteric liquid crystalline phase depends onthe type or the concentration of a chiral agent which is used togetherwith the polymerizable liquid crystal compound, a desired pitch can beobtained by adjusting the type or the concentration. Furthermore,methods described in “Introduction to Liquid Crystal Chemical Test”, p.46, edited by Japan Liquid Crystal Society, published by SigmaPublications, 2007, and “Liquid Crystal Handbook”, p. 196, LiquidCrystal Handbook Editing Committee Maruzen can be used as a method ofmeasuring the sense or the pitch of the helix.

In the mirror with an image display function of the invention, thecentral wavelength of selective reflection of the cholesteric liquidcrystal layer is different from the emission peak wavelength of theimage display device by 5 nm or greater, and preferably 10 nm orgreater. By shifting the emission peak wavelength for image display ofthe image display device from the central wavelength of selectivereflection, the light for image display can make an image bright withoutbeing reflected by the cholesteric liquid crystal layer. The emissionpeak wavelength of the image display device can be confirmed by anemission spectrum during white display of the image display device. Thepeak wavelength may be a peak wavelength in a visible light region ofthe emission spectrum, and may be, for example, any one selected fromthe group consisting of the above-described emission peak wavelength λRof red light, emission peak wavelength λG of green light, and emissionpeak wavelength λB of blue light of the image display device. Thecentral wavelength of selective reflection of the cholesteric liquidcrystal layer is preferably different from any one of theabove-described emission peak wavelength λR of red light, emission peakwavelength λG of green light, and emission peak wavelength λB of bluelight of the image display device by 5 nm or greater, and preferably 10nm or greater. In a case where the circular polarization reflectionlayer includes a plurality of cholesteric liquid crystal layers, thecentral wavelengths of selective reflection of all of the cholestericliquid crystal layers may be different from the emission peak wavelengthof the image display device by 5 nm or greater, and preferably 10 nm orgreater. For example, in a case where the image display device is afull-color display device showing an emission peak wavelength λR of redlight, an emission peak wavelength λG of green light, and an emissionpeak wavelength λB of blue light in an emission spectrum during whitedisplay, any one of the central wavelengths of selective reflection ofthe cholesteric liquid crystal layers may be different from any one ofλR, λG, and λB by 5 nm or greater, and preferably 10 nm or greater.Furthermore, in a case where the circular polarization reflection layerincludes cholesteric liquid crystal layers having different centralwavelengths of selective reflection represented by λ1, λ2, and λ3, arelationship of λB<λ1<λG<λ2<λR<λ3 is preferably satisfied.

When the circular polarization reflection layer includes a plurality ofcholesteric liquid crystal layers, a cholesteric liquid crystal layercloser to the image display device preferably has a longer centralwavelength of selective reflection. Due to this configuration, tintchange occurring when images and mirror-reflected images are obliquelyobserved can be suppressed.

In a case where the central wavelength of selective reflection of thecholesteric liquid crystal layer to be used is adjusted in accordancewith the light emitting wavelength region of the image display deviceand the use mode of the circular polarization reflection layer, a brightimage can be displayed with high light utilization efficiency. Examplesof the use mode of the circular polarization reflection layer include anincidence angle of light on the circular polarization reflection layerand an image observation direction.

As each cholesteric liquid crystal layer, a cholesteric liquid crystallayer in which the sense of the helix is right-handed or left-handed isused. The sense of the reflected circularly polarized light of thecholesteric liquid crystal layer is identical to the sense of the helix.When the circular polarization reflection layer includes a plurality ofcholesteric liquid crystal layers, the senses of the helices thereof maybe the same as each other, or a cholesteric liquid crystal layer havinga different sense of a helix may be included. As cholesteric liquidcrystal layers having a specific central wavelength of selectivereflection, cholesteric liquid crystal layers in which the sense isright-handed or left-handed, or cholesteric liquid crystal layers inwhich the sense is both right-handed and left-handed may be included.

A half-width Δλ (nm) of a selective reflection band in which selectivereflection is exhibited depends on the birefringence Δn of the liquidcrystal compound and the pitch P, and has a relationship of Δλ=Δn×Ptherewith. Therefore, the width of the selective reflection band can becontrolled by adjusting Δn. Δn can be adjusted by adjusting the type orthe mixing ratio of the polymerizable liquid crystal compound orcontrolling the temperature at the time of alignment fixing.

In order to form one type of cholesteric liquid crystal layers havingthe same central wavelength of selective reflection, a plurality ofcholesteric liquid crystal layers having the same periodicity P and thesame sense of the helix may be laminated. By laminating cholestericliquid crystal layers having the same periodicity P and the same senseof the helix, circular polarization selectivity can be increased at aspecific wavelength.

(Method of Producing Cholesteric Liquid Crystal Layer)

Hereinafter, materials and methods for producing the cholesteric liquidcrystal layer will be described.

Examples of the material used to form the cholesteric liquid crystallayer include a liquid crystal composition containing a polymerizableliquid crystal compound and a chiral agent (optical active compound).The liquid crystal composition which is further mixed with a surfactant,a polymerization initiator, or the like if necessary and dissolved in asolvent or the like is coated on a temporary support, an alignment film,a cholesteric liquid crystal layer serving as an underlayer, or thelike, and after cholesteric alignment and maturing, the liquid crystalcomposition is cured for fixing to form the cholesteric liquid crystallayer.

(Polymerizable Liquid Crystal Compound)

A rod-like liquid crystal compound may be used as the polymerizableliquid crystal compound.

Examples of the rod-like polymerizable liquid crystal compound whichforms the cholesteric liquid crystal layer include a rod-like nematicliquid crystal compound. As the rod-like nematic liquid crystalcompound, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters,benzoic acid esters, cyclohexanecarboxylic acid phenyl esters,cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines,alkoxy-substituted phenylpyrimidines, phenyl dioxanes, tolans, andalkenylcyclohexyl benzonitriles are preferably used. It is possible touse not only a low-molecular liquid crystal compound, but also ahigh-molecular liquid crystal compound.

The polymerizable liquid crystal compound is obtained by introducing apolymerizable group in a liquid crystal compound. Examples of thepolymerizable group include an unsaturated polymerizable group, an epoxygroup, and an aziridinyl group. An unsaturated polymerizable group ispreferable, and an ethylene unsaturated polymerizable group isparticularly preferable. The polymerizable group can be introduced inmolecules of a liquid crystal compound by various methods. The number ofthe polymerizable groups in the polymerizable liquid crystal compound ispreferably 1 to 6, and more preferably 1 to 3. Examples of thepolymerizable liquid crystal compound include those described inMakromol. Chem., vol. 190, p. 2255 (1989), Advanced Materials, vol. 5,p. 107 (1993), U.S. Pat. Nos. 4,683,327A, 5,622,648A, 5,770,107A,WO95/22586A, WO95/24455A, WO97/00600A, WO 98/23580A, WO98/52905A,JP1989-272551A (JP-H1-272551A), JP1994-16616A (JP-H6-16616A),JP1995-110469A (JP-H7-110469A), JP1999-80081A (JP-H11-80081A), andJP2001-328973A. Two or more types of polymerizable liquid crystalcompounds may be used in combination. Using two or more types ofpolymerizable liquid crystal compounds may contribute to lowering thealignment temperature.

The amount of the polymerizable liquid crystal compound added in theliquid crystal composition is preferably 80 to 99.9 mass %, morepreferably 85 to 99.5 mass %, and particularly preferably 90 to 99 mass% with respect to the solid content mass of the liquid crystalcomposition (mass excluding the mass of the solvent).

(Chiral Agent: Optical Active Compound)

The chiral agent functions to induce the helical structure of thecholesteric liquid crystalline phase. The chiral compound may beselected in accordance with the purpose since compounds are different inthe helix pitch or the sense of the helix to be induced.

The chiral agent is not particularly limited, and a known compound (forexample, chiral agents for TN or STN, which are described in LiquidCrystal Device Handbook, Third Chapter, 4-3 Chapter, p. 199, edited byNo. 142 Committee of Japan Society for the Promotion of Science, in1989), isosorbide, or an isomannide derivative can be used.

In general, the chiral agent contains asymmetric carbon atoms. However,an axial asymmetric compound or a planar asymmetric compound containingno asymmetric carbon atoms can also be used as a chiral agent. Examplesof the axial asymmetric compound or the planar asymmetric compoundinclude binaphthyl, helicene, paracyclophane, and their derivatives. Thechiral agent may have a polymerizable group. In a case where all of thechiral agent and the liquid crystal compound have a polymerizable group,the polymerization reaction of the polymerizable chiral agent and thepolymerizable liquid crystal compound can give a polymer having arepeating unit derived from the polymerizable liquid crystal compoundand a repeating unit derived from the chiral compound. In thisembodiment, the polymerizable group of the polymerizable chiral compoundis preferably the same as that of the polymerizable liquid crystalcompound. Accordingly, the polymerizable group of the chiral agent isalso preferably an unsaturated polymerizable group, an epoxy group, oran aziridinyl group, more preferably an unsaturated polymerizable group,and particularly preferably an ethylenic unsaturated polymerizablegroup.

The chiral agent may be a liquid crystal compound.

The content of the chiral agent in the liquid crystal composition ispreferably 0.01 mol % to 200 mol %, and more preferably 1 mol % to 30mol % of the amount of the polymerizable liquid crystal compound.

(Polymerization Initiator)

The liquid crystal composition preferably contains a polymerizationinitiator. In an embodiment in which a polymerization reaction iscarried out by ultraviolet irradiation, a polymerization initiator to beused is preferably a photopolymerization initiator capable of initiatinga polymerization reaction by ultraviolet irradiation. Examples of thephotopolymerization initiator include α-carbonyl compounds (described inU.S. Pat. Nos. 2,367,661A and 2,367,670A), acyloin ethers (described inU.S. Pat. No. 2,448,828A), α-hydrocarbon-substituted aromatic acyloincompounds (described in U.S. Pat. No. 2,722,512A), polynuclear quinonecompounds (described in U.S. Pat. Nos. 3,046,127A and 2,951,758A),combination of triarylimidazole dimer and p-aminophenylketone (describedin U.S. Pat. No. 3,549,367A), acridine and phenazine compounds(described in JP1985-105667A (JP-S60-105667A) and U.S. Pat. No.4,239,850A), and oxadiazole compounds (described in U.S. Pat. No.4,212,970A).

The content of the photopolymerization initiator in the liquid crystalcomposition is preferably 0.1 to 20 mass %, and more preferably 0.5 mass% to 5 mass % with respect to the content of the polymerizable liquidcrystal compound.

(Crosslinking Agent)

The liquid crystal composition may contain an arbitrary crosslinkingagent in order to improve the film hardness after curing and durability.As the crosslinking agent, a material which is curable with ultravioletrays, heat, moisture, or the like can be suitably used.

The crosslinking agent is not particularly limited, and can beappropriately selected in accordance with the purpose. Examples thereofinclude polyfunctional acrylate compounds such as trimethylolpropanetri(meth)acrylate and pentaerythritol tri(meth)acrylate; epoxy compoundssuch as glycidyl(meth)acrylate and ethylene glycol diglycidyl ether;aziridine compounds such as2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] and4,4-bis(ethyleneiminocarbonylamino)diphenylmethane; isocyanate compoundssuch as hexamethylene diisocyanate and biuret-type isocyanate;polyoxazoline compounds having an oxazoline group in a side chain; andalkoxysilane compounds such as vinyltrimethoxysilane andN-(2-aminoethyl) 3-aminopropyltrimethoxysilane. A known catalyst can beused depending on the reactivity of the crosslinking agent in order toenhance productivity in addition to the enhancement of the film hardnessand the durability. These may be used alone or in combination of two ormore types thereof.

The content of the crosslinking agent is preferably 3 mass % to 20 mass%, and more preferably 5 mass % to 15 mass %. In a case where thecontent of the crosslinking agent is less than 3 mass %, thecrosslinking density improving effect may not be obtained, and in a casewhere the content of the crosslinking agent is greater than 20 mass %,the stability of the cholesteric liquid crystal layer may be reduced.

(Alignment Control Agent)

In the liquid crystal composition, an alignment control agent may beadded to contribute to stably or rapidly form a cholesteric liquidcrystal layer in which planar alignment is achieved. Examples of thealignment control agent include fluorine (meth)acrylate-based polymersdescribed in paragraphs [0018] to [0043] in JP2007-272185A and compoundsrepresented by Formulae (I) to (IV) described in paragraphs [0031] to[0034] in JP2012-203237A.

The alignment control agents may be used alone or in combination of twoor more types thereof.

The amount of the alignment control agent added in the liquid crystalcomposition is preferably 0.01 mass % to 10 mass %, more preferably 0.01mass % to 5 mass %, and particularly preferably 0.02 mass % to 1 mass %with respect to the total mass of the polymerizable liquid crystalcompound.

(Other Additives)

The liquid crystal composition may contain at least one selected fromvarious additives such as a surfactant for uniformizing the filmthickness by adjusting the surface tension of the coating film and apolymerizable monomer. Furthermore, if necessary, within a range thatdoes not deteriorate the optical performance, a polymerizationinhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer,a coloring material, metal oxide particles, and the like can be added tothe liquid crystal composition.

The cholesteric liquid crystal layer can be formed in such a manner thata liquid crystal composition obtained by dissolving, in a solvent, apolymerizable liquid crystal compound, a polymerization initiator, andoptional additives such as a chiral agent and a surfactant is coated anddried on a temporary support, an alignment layer, a front surface plate,or a cholesteric liquid crystal layer produced previously to obtain acoating film, and the coating film is irradiated with active light raysto polymerize a cholesteric liquid crystalline composition and fix thecholesteric regularity. A lamination film consisting of a plurality ofcholesteric liquid crystal layers can be formed by repeating the processof producing a cholesteric liquid crystal layer.

(Solvent)

The solvent used to prepare the liquid crystal composition is notparticularly limited, and can be appropriately selected in accordancewith the purpose. An organic solvent is preferably used.

The organic solvent is not particularly limited, and can beappropriately selected in accordance with the purpose. Examples thereofinclude ketones, alkyl halides, amides, sulfoxides, heterocycliccompounds, hydrocarbons, esters, and ethers. These may be used alone orin combination of two or more types thereof. Among these, ketones areparticularly preferable in consideration of the load imposed on theenvironment.

(Coating, Alignment, Polymerization)

The method of coating a temporary support, an alignment film, acholesteric liquid crystal layer serving as an underlayer, or the likewith a liquid crystal composition is not particularly limited, and canbe appropriately selected in accordance with the purpose. Examplesthereof include a wire bar coating method, a curtain coating method, anextrusion coating method, a direct gravure coating method, a reversegravure coating method, a die coating method, a spin coating method, adip coating method, a spray coating method, and a slide coating method.Furthermore, the coating can also be performed by transferring a liquidcrystal composition, which has been separately applied onto a support.By heating the liquid crystal composition applied, the liquid crystalmolecules are aligned. The heating temperature is preferably equal to orlower than 200° C., and more preferably equal to or lower than 130° C.By this alignment, an optical thin film is obtained in which thepolymerizable liquid crystal compound is aligned in a twisted manner tohave a helical axis in a direction substantially perpendicular to thesurface of the film.

The aligned liquid crystal compound can be further subjected topolymerization to cure the liquid crystal composition. Thepolymerization may be any one of thermal polymerization andphotopolymerization by light irradiation, but is preferablyphotopolymerization. Ultraviolet rays are preferably used for lightirradiation. The irradiation energy is preferably 20 mJ/cm² to 50 J/cm²,and more preferably 100 mJ/cm² to 1,500 mJ/cm². In order to acceleratethe photopolymerization reaction, the light irradiation may be performedunder heating conditions or in a nitrogen atmosphere. The wavelength ofthe ultraviolet rays for irradiation is preferably 350 nm to 430 nm.From the viewpoint of stability, the rate of the polymerization reactionis preferably high. The rate of the polymerization reaction ispreferably equal to or higher than 70%, and more preferably equal to orhigher than 80%. The rate of the polymerization reaction can bedetermined by measuring the consumption rate of polymerizable functionalgroups by using an infrared (IR) absorption spectrum.

The thickness of each cholesteric liquid crystal layer is notparticularly limited as long as it is in such a range that theabove-described characteristics are exhibited. The thickness ispreferably in a range of 1.0 μm to 150 μm, and more preferably 4.0 μm to100 μm.

In the lamination of a plurality of cholesteric liquid crystal layers, aprocess including: directly coating a surface of a previous cholestericliquid crystal layer formed as described above with a liquid crystalcomposition containing a polymerizable liquid crystal compound and thelike; alignment; and fixing may be repeated. Otherwise, a cholestericliquid crystal layer produced separately may be laminated using anadhesive or the like. However, the former is preferable. The reason forthis is that in a case where a cholesteric liquid crystal layer isformed so as to be in direct contact with a surface of a cholestericliquid crystal layer formed previously, an alignment direction of liquidcrystal molecules on the air interface side of the cholesteric liquidcrystal layer formed previously is identical to an alignment directionof liquid crystal molecules on the lower side of the cholesteric liquidcrystal layer formed thereon, and the polarization characteristics ofthe laminate of the cholesteric liquid crystal layers are enhanced. Inaddition, the reason for this is that, in general, in a case where anadhesive layer provided to have a film thickness of 0.5 to 10 μm isused, interference unevenness resulting from thickness unevenness of theadhesive layer may be observed, and thus it is preferable that thelamination is performed without using the adhesive layer.

(Temporary Support, Alignment Layer)

The liquid crystal composition may be coated on a surface of a temporarysupport or an alignment layer formed on the surface of the temporarysupport to form a cholesteric liquid crystal layer. The temporarysupport, or the temporary support and the alignment layer may be peeledoff after the formation of the cholesteric liquid crystal layer.

Examples of the temporary support include polyester such as polyethyleneterephthalate (PET), polycarbonate, an acrylic resin, an epoxy resin,polyurethane, polyamide, polyolefin, a cellulose derivative, silicone,and a glass plate.

The alignment layer can be provided by means of rubbing of an organiccompound (resin such as polyimide, polyvinyl alcohol, polyester,polyarylate, polyamideimide, polyether imide, polyamide, and modifiedpolyamide) such as a polymer, oblique vapor deposition of an inorganiccompound, formation of a layer having microgrooves, or accumulation ofan organic compound (for example, n-tricosanoic acid,dioctadecylmethylammonium chloride, or methyl stearate) by aLangmuir-Blodgett method (LB film). Furthermore, an alignment layer maybe used which obtains an alignment function by the application of anelectric field or a magnetic field or by being irradiated with light.

Particularly, it is preferable that an alignment layer composed of apolymer is rubbed, and then the rubbed surface is coated with the liquidcrystal composition. The rubbing can be performed by rubbing the surfaceof the polymer layer several times with paper or cloth in a certaindirection.

The liquid crystal composition may be coated on a surface of a temporarysupport or a rubbed surface of a temporary support without providing thealignment layer.

The thickness of the alignment layer is preferably 0.01 to 5 μm, andmore preferably 0.05 to 2 μm.

[Front Surface Plate]

The mirror with an image display function of the invention has a frontsurface plate.

The front surface plate is not particularly limited. A glass plate or aplastic plate used to produce a usual mirror can be used as the frontsurface plate. The front surface plate is preferably transparent in avisible light region and preferably has low birefringence. Here,transparent in a visible light region means that the light transmittancein the visible light region is 80% or greater, and preferably 85% orgreater. The light transmittance which is used as a measure oftransparency is obtained using the method described in JIS A5759. Thatis, the transmittance is measured at wavelengths of 380 nm to 780 nmusing a spectrophotometer, and multiplied by a weight value coefficientobtained from a spectral distribution of the International Commission onIllumination (CIE) daylight D65 and a wavelength distribution and awavelength interval of CIE spectral luminous efficiency for photopicvision to calculate a weighted average, and thus the visible lighttransmittance is obtained. Examples of the plastic film includepolycarbonate, an acrylic resin, an epoxy resin, polyurethane,polyamide, polyolefin, a cellulose derivative, and silicone.

The film thickness of the front surface plate may be approximately 100μm to 10 mm, preferably 200 μm to 5 mm, and more preferably 500 μm to 2mm.

[Adhesive Layer]

The mirror with an image display function of the invention may includean adhesive layer for adhesion between the image display device and thecircular polarization reflection layer, between the circularpolarization reflection layer and the front surface plate, and betweenother respective layers. The adhesive layer may be formed from anadhesive.

Adhesives are classified into hot-melt types, thermosetting types,photocurable types, reaction-curable types, and pressure-sensitive typeswhich do not require curing. As the materials of these adhesives, it ispossible to use compounds based on acrylate, urethane, urethaneacrylate, epoxy, epoxy acrylate, polyolefin, modified olefin,polypropylene, ethylene vinyl alcohol, vinyl chloride, chloroprenerubber, cyanoacrylate, polyamide, polyimide, polystyrene, polyvinylbutyral, or the like. From the viewpoint of workability andproductivity, photocuring is preferable as the curing method. From theviewpoint of optical transparency and heat resistance, materials basedon acrylate, urethane acrylate, epoxy acrylate, or the like arepreferably used.

<Half Mirror>

A half mirror can be formed using a circular polarization reflectionlayer and a front surface plate. A half mirror may be produced byforming a circular polarization reflection layer on a front surfaceplate, or by transferring a circular polarization reflection layerformed on a temporary support onto a front surface plate. For example, ahalf mirror can be obtained in such a manner that on a temporarysupport, a cholesteric liquid crystal layer or a laminate of cholestericliquid crystal layers is formed to form a circular polarizationreflection layer, a front surface plate is adhered to a surface of thecircular polarization reflection layer, and then the temporary supportis peeled off if necessary. The temporary support may function as aprotective film until the circular polarization reflection layer isadhered to the image display device.

<Method of Producing Mirror with Image Display Function>

The mirror with an image display function of the invention can beproduced by, for example, positioning the circular polarizationreflection layer side of a half mirror including a circular polarizationreflection layer and a front surface plate on an image display surfaceof an image display device. Then, if necessary, the image display deviceand the half mirror may be formed integrally with each other. The imagedisplay device and the half mirror may be formed integrally with eachother through connection or adhesion at an outer frame or a hinge.

<Use of Mirror with Image Display Function>

The use of the mirror with an image display function of the invention isnot particularly limited. For example, it can be used as a securitymirror, a mirror of a hair salon or a barbershop, or the like, and candisplay an image such as texture information, a still image, or a motionpicture. In addition, the mirror with an image display function of theinvention may be a vehicle rearview mirror, or may be used for atelevision, a personal computer, a smartphone, a cell phone, or thelike.

EXAMPLES

Hereinafter, the invention will be described in more detail withreference to examples. The materials, the reagents, the amounts ofmaterials, the proportions thereof, the operations, and the like whichwill be shown in the following examples can be appropriately modifiedwithin a range not departing from the gist of the invention.Accordingly, the scope of the invention is not limited to the followingexamples.

<Preparation of Cholesteric Liquid Crystalline Mixture (R)>

The following Compound 1, Compound 2, Fluorine-based HorizontalAlignment Agent 1, Fluorine-based Horizontal Alignment Agent 2, chiralagent, polymerization initiator, solvent (methyl ethyl ketone) weremixed to prepare a coating liquid having the following composition.

Compound 1 80 parts by mass Compound 2 20 parts by mass Fluorine-basedHorizontal Alignment Agent 1 0.1 parts by mass Fluorine-based HorizontalAlignment Agent 2 0.007 parts by mass Right-Turning Chiral Agent LC756(manufactured by BASF) The amount thereof was adjusted in accordancewith a target reflection wavelength. Polymerization Initiator IRGACURE819 (manufactured by BASF) 3 parts by mass Solvent (methyl ethyl ketone)The amount thereof was set such that the concentration of the solute was30 mass %. Compound 1

Compound 2

Fluorine-based Horizontal Alignment Agent 1

Fluorine-based Horizontal Alignment Agent 2

<Preparation of Cholesteric Liquid Crystalline Mixture (L)>

Compound 1, Compound 2, Fluorine-based Horizontal Alignment Agent 1,Fluorine-based Horizontal Alignment Agent 2, a chiral agent, apolymerization initiator, and a solvent (methyl ethyl ketone) were mixedto prepare a coating liquid having the following composition.

Compound 1 80 parts by mass Compound 2 20 parts by mass Fluorine-basedHorizontal Alignment Agent 1 0.1 parts by mass Fluorine-based HorizontalAlignment Agent 2 0.007 parts by mass The following Left-Turning ChiralAgent (A) The amount thereof was adjusted in accordance with a targetreflection wavelength. Polymerization Initiator IRGACURE 819(manufactured by BASF) 3 parts by mass Solvent (methyl ethyl ketone) Theamount thereof was set such that the concentration of the solute was 30mass %. Left-Turning Chiral Agent (A)

(Bu = n-Butyl Group)

Coating liquids (R1) to (R9) were prepared by adjusting the prescribedamount of the chiral agent LC-756 of the mixture (R). Using each coatingliquid, a single cholesteric liquid crystal layer was produced on atemporary support in the same manner as in the following production of acircular polarization reflection layer, and reflection characteristicswere confirmed. All of the produced cholesteric liquid crystal layerswere right-circular polarization reflection layers, and the centralreflection wavelengths were as in the following Table 1.

TABLE 1 Coating Liquid Central Reflection Wavelength Coating Liquid (R1)450 nm Coating Liquid (R2) 455 nm Coating Liquid (R3) 465 nm CoatingLiquid (R4) 540 nm Coating Liquid (R5) 545 nm Coating Liquid (R6) 555 nmCoating Liquid (R7) 630 nm Coating Liquid (R8) 635 nm Coating Liquid(R9) 645 nm

In addition, coating liquids (L1) to (L9) were prepared by adjusting theprescribed amount of the chiral agent A of the mixture (L). Using eachcoating liquid, a single cholesteric liquid crystal layer was producedon a temporary support in the same manner as in the following productionof a circular polarization reflection layer, and reflectioncharacteristics were confirmed. All of the produced cholesteric liquidcrystal layers were left-circular polarization reflection layers, andthe central reflection wavelengths were as in the following Table 2.

TABLE 2 Coating Liquid Central Reflection Wavelength Coating Liquid (L1)450 nm Coating Liquid (L2) 455 nm Coating Liquid (L3) 465 nm CoatingLiquid (L4) 540 nm Coating Liquid (L5) 545 nm Coating Liquid (L6) 555 nmCoating Liquid (L7) 630 nm Coating Liquid (L8) 635 nm Coating Liquid(L9) 645 nm

<Formation of Circular Polarization Reflection Layer>

Using the prepared coating liquid, a circular polarization reflectionlayer was produced in accordance with the following procedures. A PETfilm (no undercoat layer, thickness: 75 μm) manufactured by FujifilmCorporation was rubbed and used as a temporary support.

(1) A coating liquid for a first layer shown in Table 3 was coated on arubbed surface of a temporary support at room temperature using a wirebar such that the thickness of the film after drying was 4.0 μm.

(2) After the solvent was removed by drying for 30 seconds at roomtemperature, the film was heated for 2 minutes in an atmosphere at 125°C., and then a cholesteric liquid crystalline phase was obtained at 95°C. Next, UV irradiation was performed for 6 to 12 seconds with an outputof 60% using an electrodeless lamp “D-BULB” (90 W/cm) manufactured byFusion UV Systems to fix the cholesteric liquid crystalline phase, andthus a cholesteric liquid crystal layer was produced. The cholestericliquid crystal layer was cooled to the room temperature.

(3) A coating liquid for a second layer shown in Table 3 was coated on asurface of the obtained cholesteric liquid crystal layer, and theabove-described processes (1) and (2) were repeated. A coating liquidfor a third layer shown in Table 3 was coated on a surface of theobtained second cholesteric liquid crystal layer, and theabove-described processes (1) and (2) were repeated to form a circularpolarization reflection layer consisting of three cholesteric liquidcrystal layers on the temporary support.

<Bonding of Circular Polarization Reflection Layer and Front SurfacePlate>

A UV-curable adhesive Exp. U12034-6 manufactured by DIC CORPORATION wascoated on a surface of the cholesteric liquid crystal layer of thelaminate produced in the above description using a wire bar at roomtemperature such that the thickness of the dried film after drying was 5μm. This coated surface and a front surface plate (FRONT GLASS FL2manufactured by Central Glass Co., Ltd., thickness: 2 mm) were bondedsuch that air bubbles were prevented from entering therebetween. Then,UV irradiation was performed for 6 to 12 seconds with an output of 60%using a D-BULB (lamp, 90 W/cm) manufactured by Fusion UV Systems at 50°C. Then, the temporary support was peeled off, and thus a half mirrorwas produced.

<Bonding of Commercially Available Reflection-Type Mirror Film and FrontSurface Plate>

An APF sold by 3M United States or a commercially availablemetal-deposited mirror was used and bonded to a front surface plate(FRONT GLASS FL2 manufactured by Central Glass Co., Ltd., thickness: 2mm) through a method using the same UV-curable adhesive as above, andthus a half mirror was produced.

<Evaluation of Mirror with Image Display Function>

Each produced half mirror was disposed such that the circularpolarization reflection plate was superposed on an image display surfaceof a liquid crystal display device (LCD) (manufactured by Apple Inc.,iPad Air) (emission peak wavelength, 450 nm (B), 540 nm (G), 630 nm (R))and the front surface plate was on the opposite side (nearest to anobserver). A half mirror using an APF was disposed such that thetransmission axis of a LCD and the transmission axis of the APF wereidentical to each other. The configurations were evaluated as follows asExamples 1 to 4 and Comparative Examples 1 to 4. The results are shownin Table 3.

<Evaluation>

(Brightness)

The front luminance during white display of the liquid crystal displaydevice was measured using a measuring machine (EZ-Contrast 160Dmanufactured by ELDIM) as in the description in a paragraph [0180] inJP2009-93166A. “(The front luminance after the installation of the halfmirror/the front luminance before the installation of the halfmirror)×100%” was obtained for evaluation based on the followingstandards.

A: 100% or less and greater than 50%

B: 50% or less and greater than 40%

C: 40% or less

(Front Tint of Image, Possibility of Visual Recognition ofMirror-Reflected Image)

The visual evaluation was performed through polarized sunglasses.

Regarding the evaluation of the front tint of an image, an example inwhich color balance and the like did not considerably change incomparison with an image when viewed without the polarized sunglasseswas evaluated to be “good”, and a case where color balance and the likechanged was evaluated to be “bad”.

Regarding the possibility of the visual recognition of amirror-reflected image, an example in which even in a case where theimage display surface of the mirror with an image display function wasrotated about a normal line thereof with respect to the polarizedsunglasses, a mirror-reflected image could be always visually recognizedwas evaluated to be “possible”, and an example in which there was adirection in which the mirror-reflected image could not be visuallyrecognized was evaluated to be “not possible”.

TABLE 3 First Layer Second Layer Third Layer (difference (difference(difference between between between central central central reflectionreflection reflection Sunglasses Evaluation wavelength wavelengthwavelength Possibility of and and and Visual wavelength wavelengthwavelength Front Recognition of of B of of G of of R of Tint ofMirror-Reflected LCD) LCD) LCD) Brightness Image Image Comparative R1 R4R7 C (40%) Good Possible Example 1 (0 nm) (0 nm) (0 nm) Example 1 R2 R5R8 B (45%) Good Possible (5 nm) (5 nm) (5 nm) Example 2 R3 R6 R9 A (55%)Good Possible (15 nm) (15 nm) (15 nm) Comparative L1 L4 L7 C (40%) GoodPossible Example 2 (0 nm) (0 nm) (0 nm) Example 3 L2 L5 L8 B (45%) GoodPossible (5 nm) (5 nm) (5 nm) Example 4 L3 L6 L9 A (55%) Good Possible(15 nm) (15 nm) (15 nm) Comparative APF A (85%) Good Not PossibleExample 3 Comparative Metal-Deposited C (38%) Good Possible Example 4Half Mirror

What is claimed is:
 1. A mirror with an image display functioncomprising, in this order: an image display device; a circularpolarization reflection layer; and a front surface plate made of glassor plastic, wherein the circular polarization reflection layer includesa cholesteric liquid crystal layer, the cholesteric liquid crystal layerhas a central wavelength of selective reflection in a visible lightregion, and the central wavelength is different from an emission peakwavelength of the image display device by 5 nm or greater.
 2. The mirrorwith an image display function according to claim 1, wherein thecircular polarization reflection layer includes two or more cholestericliquid crystal layers, and the two or more cholesteric liquid crystallayers have different central wavelengths of selective reflection. 3.The mirror with an image display function according to claim 2, whereinthe two or more cholesteric liquid crystal layers are in direct contactwith each other.
 4. The mirror with an image display function accordingto claim 1, wherein the circular polarization reflection layer includesthree or more cholesteric liquid crystal layers, and the three or morecholesteric liquid crystal layers have different central wavelengths ofselective reflection.
 5. The mirror with an image display functionaccording to claim 3, wherein the circular polarization reflection layerincludes three or more cholesteric liquid crystal layers, and the threeor more cholesteric liquid crystal layers have different centralwavelengths of selective reflection.
 6. The mirror with an image displayfunction according to claim 4, wherein the image display device shows anemission peak wavelength λR of red light, an emission peak wavelength λGof green light, and an emission peak wavelength λB of blue light in anemission spectrum during white display, and any one of the centralwavelengths of selective reflection of the cholesteric liquid crystallayers is different from any one of λR, λG, and λB by 5 nm or greater.7. The mirror with an image display function according to claim 5,wherein the image display device shows an emission peak wavelength λR ofred light, an emission peak wavelength λG of green light, and anemission peak wavelength λB of blue light in an emission spectrum duringwhite display, and any one of the central wavelengths of selectivereflection of the cholesteric liquid crystal layers is different fromany one of λR, λG, and λB by 5 nm or greater.
 8. The mirror with animage display function according to claim 6, wherein the circularpolarization reflection layer includes layers in which cholestericliquid crystalline phases having λ1, λ2, and λ3, respectively, are fixedas different central wavelengths of selective reflection, and arelationship of λB<λ1<λG<λ2<λR<λ3 is satisfied.
 9. The mirror with animage display function according to claim 7, wherein the circularpolarization reflection layer includes layers in which cholestericliquid crystalline phases having λ1, λ2, and λ3, respectively, are fixedas different central wavelengths of selective reflection, and arelationship of λB<λ1<λG<λ2<λR<λ3 is satisfied.
 10. The mirror with animage display function according to claim 6, wherein in the circularpolarization reflection layer, a cholesteric liquid crystal layer havinga longer central wavelength of selective reflection is disposed closerto the image display device.
 11. The mirror with an image displayfunction according to claim 8, wherein in the circular polarizationreflection layer, a cholesteric liquid crystal layer having a longercentral wavelength of selective reflection is disposed closer to theimage display device.
 12. The mirror with an image display functionaccording to claim 9, wherein in the circular polarization reflectionlayer, a cholesteric liquid crystal layer having a longer centralwavelength of selective reflection is disposed closer to the imagedisplay device.
 13. The mirror with an image display function accordingto claim 1, wherein the circular polarization reflection layer includesa cholesteric liquid crystal layer having a central wavelength ofselective reflection in an infrared light region.
 14. The mirror with animage display function according to claim 6, wherein the circularpolarization reflection layer includes a cholesteric liquid crystallayer having a central wavelength of selective reflection in an infraredlight region.
 15. The mirror with an image display function according toclaim 8, wherein the circular polarization reflection layer includes acholesteric liquid crystal layer having a central wavelength ofselective reflection in an infrared light region.
 16. The mirror with animage display function according to claim 1, wherein the image displaydevice and the circular polarization reflection layer are directlyadhered to each other through an adhesive layer.
 17. The mirror with animage display function according to claim 1, which has an outer frame.18. The mirror with an image display function according to claim 6,which has an outer frame.
 19. The mirror with an image display functionaccording to claim 8, which has an outer frame.
 20. The mirror with animage display function according to claim 10, which has an outer frame.